Mud volcanoes of Italy

The locations and information about the sizes of 61 mud volcanoes on the Italian mainland and Sicily, plus an area of mud diapirism in the Italian Adriatic Sea, are presented. Data about the emission products are also provided. The majority of these mud volcanoes are found where thick sedimentary sequences occur within a zone of tectonic compression associated with local plate tectonic activity: the movement of the Adriatic microplate between the converging African and Eurasian plates. The principal gas emitted by these mud volcanoes is methane, which probably originates from deep within the sediments. Other mud volcanoes, associated with igneous volcanism, produce mainly carbon dioxide. The mud diapirs in the Adriatic Sea are thought to form as a result of the mobilization of shallow gassy sediments. It has been shown that radon emissions from mud volcanoes are indicators of forthcoming earthquake events. Copyright © 2004 John Wiley & Sons, Ltd.     

Known and unknown earthquakes through some European periodicals of the eighteenth century

Since the eighteenth century, pioneer seismologists have used information from the periodical press to compile their lists of European earthquakes. A systematic reading of three eighteenth century periodicals –Gaceta de Madrid (1701–1750), Gazeta de Lisboa (1715–1751) and Mercure de France (1732–1763) – has been carried out in the frame of the EC project ‘Review of Historical Seismicity in Europe (RHISE)’. The retrieval of earthquake records provides data on European and Mediterranean earthquakes. Sources and records are here analysed to verify their reliability and to understand the significance of the earthquake information they supply. Special attention has been paid to earthquakes that affected Italian territory, by means of a comparison between records and space-time, intensity parameters of the Italian seismic catalogue: this comparison shows that about 45% of the earthquakes mentioned by the periodicals are unknown in the Italian catalogue, and that 30% of them are damaging earthquakes.     

The carbonate fraction in carbonatitic Italian lamprophyres

Alkaline and ultramafic lamprophyres represent the majority of pre-Pleistocene alkaline mafic magmatic activity in Italy and have been described from several localities. The age of magmatism ranges from Triassic to Lower Oligocene. Some contain appreciable amounts of carbonate. The primary carbonate of the Italian carbonatitic lamprophyres is mainly Sr- or Mn-rich calcite that occurs mostly as immiscible ocelli or as groundmass. Its textural occurrence, composition, and relationship with co-precipitating silicate phases is taken as evidence of an igneous origin. Low BaO and REE contents in the carbonate are explained by early crystallization of essential mica and subordinate apatite. Whole rock analyses and isotopic data (Rukhlov, A.S., Bell, K., Vichi, G., Stoppa, F., submitted for publication. The heterogeneous deep mantle: the Sr, Pb and Nd isotopic evidence from Early Cretaceous alkaline lamprophyres of Southern Tuscany, Italy. Lithos.) suggest a mantle origin for these rocks and rule out contamination in either high or low pressure regimes. The bulk compositions of the carbonatitic lamprophyres have high HFSE / LILE and LREE / HREE ratios and although the abundances of these elements are generally lower than for carbonatites s.s., they are comparable with the abundances in other ‘carbonate-free’ Italian lamprophyres and Italian carbonatites, suggesting similar mantle sources. Moreover, the age of the Italian lamprophyres, ranging from Middle Triassic to Lower Oligocene, is much greater than the Pleistocene age of Italian carbonatites and indicates that the source remained similar over a long time span.     

The Geologic Time Scale and the Italian stratigraphic record

The construction of the Geologic Time Scale (GTS) is a titanic scientific challenge that has been under way for two centuries and will require much dedicated effort in the future. Italy preserves a paramount stratigraphic record of Mesozoic and Cenozoic marine sediments that have been significant in the development of the modern GTS. The Italian stratigraphic record has been histori-cally important in introducing and defining the standard Chronostratigraphic Units (CUs) of the Neogene and Quaternary. Pelagic successions from Northern Apen-nines and Southern Alps have been used in the seventies for integrating the late Cretaceous-Paleogene Geomag-netic Polarity Time Scale (GPTS) with planktonic microfossil biostratieraohv and standard CUs. This was a major contribution to the construction of a new gener-ation of GTS based on integrated magnetobiochronol-ogy. The middle Miocene to early Pleistocene marinerecord from Sicily and southern Italy has been funda-mental for establishing the recently developed Astro-nomical Time Scale (ATS). In prospect, there are many potentials still to be exploited in the Italian marine stratigraphic record for implementing the GTS by defin-ing GSSPs of various CUs, improving magneto-biochronology and extending downwards the ATS.     

Local- and global-scale seismic analyses of historical masonry compounds in San Pio delle Camere (L’Aquila,Italy)

Masonry building aggregates are large parts of the Italian building heritage often designed without respecting seismic criteria. The current seismic Italian code does not foresee a clear calculation method to predict their static nonlinear behaviour. For this reason, in this paper firstly, a simple methodology to forecast the seismic response of masonry aggregates in San Pio delle Camere (L’Aquila, Italy) has been set up starting from the provisions of the Italian Guidelines on Cultural Heritage. The implemented procedure has been calibrated on the results of two FEM structural analysis programs used to investigate three masonry building compounds. As a result, a design chart used to correctly predict the base shear of aggregate masonry units starting from code provisions has been set up. Later on, the large-scale seismic vulnerability and damage appraisal of the inspected historical centre has been done on the basis of a quick methodology, already implemented and experienced by the author in some historical centres of the Campania region. The analysis result was a numerical correlation between vulnerability index and mean damage grade of examined building compounds. In particular, a damage forecast under numerical way has been firstly estimated and then compared with the real one. The post-earthquake scenario has represented an ideal term of comparison for effectively testing the reliability of the employed technique, which should be further extended to other Italian historical centres.     

Quality assessment of the Italian Landslide Inventory using GIS processing

Landslides constitute one of the most important natural hazards in Italy as they are widespread and result in considerable damage and fatalities every year. The Italian Landslide Inventory (IFFI) Project was launched in 1999 with the aim of identifying and mapping landslides over the entire Italian territory. The inventory currently holds over 480,000 landslides and has been available by means of Web services since 2005. The aim of this study is to define quality indices for evaluation of the homogeneity and completeness of the IFFI database. In order to estimate the completeness of the landslide attribute information, a heuristic approach has been used to assign weighting values to significant parameters selected from the landslide data sheet. The completeness and homogeneity of the landslide mapping has been evaluated by means of three different methods: an area-frequency distribution analysis; the proximity of the landslides surveyed to urban areas; variation of the landslide index within the same lithology. The quality indices have allowed identification of areas with a high level of completeness and critical areas in which the data collected have been underestimated or are not very accurate. The quality assessment of collected and stored data is essential in order to use the IFFI database for definition and implementation of landslide susceptibility models and for land use planning and management.     

Local- and global-scale seismic analyses of historical masonry compounds in San Pio delle Camere (L’Aquila,Italy)

Masonry building aggregates are large parts of the Italian building heritage often designed without respecting seismic criteria. The current seismic Italian code does not foresee a clear calculation method to predict their static nonlinear behaviour. For this reason, in this paper firstly, a simple methodology to forecast the seismic response of masonry aggregates in San Pio delle Camere (L’Aquila, Italy) has been set up starting from the provisions of the Italian Guidelines on Cultural Heritage. The implemented procedure has been calibrated on the results of two FEM structural analysis programs used to investigate three masonry building compounds. As a result, a design chart used to correctly predict the base shear of aggregate masonry units starting from code provisions has been set up. Later on, the large-scale seismic vulnerability and damage appraisal of the inspected historical centre has been done on the basis of a quick methodology, already implemented and experienced by the author in some historical centres of the Campania region. The analysis result was a numerical correlation between vulnerability index and mean damage grade of examined building compounds. In particular, a damage forecast under numerical way has been firstly estimated and then compared with the real one. The post-earthquake scenario has represented an ideal term of comparison for effectively testing the reliability of the employed technique, which should be further extended to other Italian historical centres.

     

Problems in assessing macroseismic intensity from historical earthquake records

This paper tackles the problems connected with the use of macroseismic scales, with particular attention to MSK. Intensity estimates are in principle affected by uncertainties which are seldom quantified in practice. In the case of two localities (Scisciano and Orciano) damaged by two Italian earthquakes (1741, Fabriano and 1846, Orciano), which have a good historical documentation, the difficulties of obtaining the data necessary for MSK evaluation have been analysed. In order to assess the maximum range of uncertainty the data have been analysed in two extreme scenarios. Finally a comparison between intensity assigned using the MSK and MCS scales is analysed.     

Seismogeological effects and macroseismic fields

Several seismogeological effects of earthquakes on the environment have been collected by means of the ING macroseismic procedure. The fast and easy collection of information about ground and hydrological effects constitutes a complementary instrument in assessing the effects on human structures and the environment, and, ultimately, establishing intensity values. In this paper the distribution of seismogeological effects within intensity values has been verified, using data from three moderate Italian earthquakes; the density of the same effects are then discussed in comparison with isoseismal maps.     

The inexact catalogue: the study of more than 1700 earthquakes from the XI to the XX century in Italy*

The relevant results of the study of more than 1700 Italian historical earthquakes from the year 1000 to 1982 are presented here. The research was carried out from 1983 to 1987 as part of a study promoted by ENEL (the National Electricity Board) for the seismic siting of nuclear power plants. A single coherent project has been developed, that involved 111 historical researchers who operated in 813 research centres in Italy and abroad. Problems such as the methods, research, analysis and interpretation of the numerous and various effects caused both by destructive and non-destructive earthquakes recorded in the historical sources, have been considered on a large scale for the first time. The earthquake records, collected in a data bank and interpreted according to a multi-disciplinary historical and seismological approach, have allowed the detailed reconstruction of the location and chronology of both individual and repeated events. This major research study has allowed us to evaluate the inexactness of the present Catalogue of Italian earthquakes in relation to the parameters of intensity, location and dating. From the synthesis of the results of the revision emerged sufficient information to value the reliability of the present Catalogue. TERRA Nova (1989) 1 , 151–162.     

Geology and time in renaissance

The 32nd session of the International Geological Congress (IGC) will be held in Florence, Italy, on August 20-28, 2004. It will be the second time for Italy to host the IGC, the first occasion having been the 2nd IGC session, held in Bologna in 1881. In the intervening 124 years, Italian geosciences have made great progress and have gained a leading position in many fields. Situated near the middle of the Mediterranean Sea, Florence will     

Rare earth elements in high-grade metamorphic rocks from the western Alps

A sequence of amphibolite to granulite facies metasedimentary and mafic metaigneous rocks from the western Italian Alps has been analysed for rare earth elements (REE). In this sequence, the metasedimentary granulites have probably been affected by a melting event while the metaigneous granulites remained unaffected. Metasedimentary granulites have a less fractionated chondrite-normalized REE pattern than equivalent amphibolite facies rocks. The granulites tend to have a higher content of heavy REE and lower abundances of light REE (LREE). The leucosomes of migmatitic granulites have lower REE content than the melanocratic bands and both these rock types have variable relative abundances of Eu. The mafic granulites have LREE enriched patterns while the amphibolites are slightly depleted in LREE. The differences between the mafic granulites and amphibolites are probably of pre-metamorphic origin.     

Assessment of tsunami hazard in the Italian seas

A method for the evaluation of tsunami potential in the seas surrounding Italy is presented. A major difficulty for performing reliable estimates of tsunami occurrence is that the existing tsunami catalog for Italy includes a small number of cases. This is due partly to the catalog incompleteness, strangely more pronounced in our century, and partly to the relative infrequency of tsunamis along the Italian seas. Evaluation of tsunami activity is therefore deduced by complementing the tsunami catalog data with data on seismicity that are by far more abundant and reliable. Analysis of seismicity and assessment of earthquake rate in coastal and submarine regions form the basis of the present method to perform tsunami potential estimates for Italy. One essential limitation of the method is that only tsunamis of seismic origin are taken into account, which leads to an underestimation of the tsunami potential. Since tsunamis generated by earthquakes are much more frequent than events produced by slumps or volcanic eruptions, the underestimation is not dramatic and very likely affects only a limited portion of the Italian coasts. In the present application of the method, eight separate regions have been considered that together cover all the coasts of Italy. In each region, seismicity has been independently examined and the earthquake potential has been calculated in small 20 × 20 cells. Then, on the basis of suitable assumptions, tsunami potential has been evaluated in each cell. According to this study, the Italian coasts that are the most exposed to the attacks of locally generated tsunamis are to be found in the Messina Straits, in Tyrrhenian coasts of Calabria, in the Ionian Sicilian coasts around Catania, and in the Gargano promontory in the Southern Adriatic Sea. Furthermore, this study confirms that the Northern Adriatic Sea has a low level of tsunami potential, in agreement with recent studies emphasizing that the large historical events concerning this region included in the first versions of the Italian tsunami catalog are largely overestimated and must be decreased.     

The unlikely independence of Northern Italy

The past fifty years have seen several elements and factors leading to the current homogenization of Italian society: the internal migration from South to North, the development of a more and more industrial and affluent society, the increase of links with Europe/World culture and economy. Nevertheless in the last decade in Northern Italy emerged the political phenomenon of autonomist parties, in particular the most successful of them: the Lega Nord. This success happened in parallel with the loss of power by traditional government parties, also as a consequence of the trial against corruption held in Milan at the beginning of the '90. Italian politics is in turmoil and it is impossible to forecast the duration or even its end. The problem is to determine the most significant elements, and which factors have the greatest effect on the current reality, also to be able to venture a prediction regarding trends. The paper suggests some ethno-nationalism evaluation criteria, useful to assess the more or less successful geopolitical dynamics where there are separatist claims. According with those criteria the Northern Italian political situation has been briefly described and evaluated, with particular attention to electoral results of the Lega Nord party. These results show a well defined geographical distribution and hence the minority condition in the North of the separatist supporters. The actual political debate in Italy has the aim to change some parts of the Constitution in the sense of federalism; it can be a sufficient reply to secessionist claims and it can make the independence of Northern Italy unlikely.     

L'organisation capitaliste du territoire et le problème du logement en Italie

The capitalistic organization of territory and the housing problem in Italy.This paper provides the first results of a research programme regarding the selective and spatially differentiated use of the Italian territory by private capital in the housing sector.According to the 1971 census, in Italy there were 63,8 million rooms for 53,2 million inhabitants. As regards the 1951 census the increase of rooms has been of 26,5 million, i.e. of 70.9%, as against an increase of 15,6% of the population. In this period the investment in dwelling-houses has represented about 30% of total fixed investments which is more than in the other E.E.C. countries.The Italian building stock (with a medium average of 1.2 rooms per inhabitant), is theoretically sufficient to satisfy the population needs. This ratio, however, drops to 1.06 if we exclude the 7.6 million rooms in non-inhabited houses (“holiday houses”, new unsold houses, abandoned homes because of emigration or because of their poor conditions).Moreover, more than one third of the Italian population lives in overcrowded conditions (less than one room per person) and poor standard houses are 40% of the total.This is not only due to the fact that public investments in the housing sector have been insignificant (6% in the last ten years), or to the unequal social distribution of revenue, but also, moreover, to the speculative character of the building activity.The economic analysis shows that between 1951 and 1971, in the expansive stages of housing production, net incomes of the building and land sector have increased more rapidly than the total earned incomes and that they have been higher than the amount of investments in the sector. So, building and land estate rent have been among the main components of the Italian capitalistic accumulation through the exporpriation of a prominent share of wages. At the same time, the ever increasing growth in housing prices both for sale and for rent has forbidden the fulfilment of the needs of the lower classes, extending in an abnormal way the production of luxury and “holiday houses” to satisfy the requirements of the higher classes. This is the cause of the above mentioned contradiction between the amount of the unused or subused building stock and the existence of a large number of sub-standard and/or overcrowded houses.This mechanism of accumulation-expropriation worked because of a specific spatial structure. Its main character consists in a strong geographical concentration of the basic activities and of the population. 53.3% of 1960–1971 housing production has concentrated in 4.7% of the Italian communes with more than 20,000 inhabitants.The analysis carried out on a stratified sample including 1,524 communes allowed us to reach the following results: 1. We find situations of greater unsatisfaction of the needs in the largest industrial metropolitan north-western areas and in the underdeveloped southern communes with strong emigrations. 2. We have had the highest offer for houses, as regards the needs, in the communes with less than 5,000 inhabitants, in the communes with less than 250,000 inhabitants, with prevalently tertiary functions, and in the districts where development is more equilibrated, from a territorial point of view (i.e.: north-eastern Italy). 3. The mechanism of accumulation-expropriation worked mainly in the industrial areas and it grows at the ever increasing growth of agglomerations and urban overcrowding, determined by strong migratory flows. 4. Building activity of tertiary communes has been led, mainly, by the higher-class expansion of consumptions. 5. The same kind of demand has given rise to the strong increase of “holiday houses” which interests large periurban, coastal and Alpine areas. 6. The housing sector becomes in this way a component of territorial disequilibriums, caused by the industrial and tertiary polarization and it is inclined to enlarge them by the artful increase of urban rent. 7. This use of territory has the aim to encourage incomes removal among different social classes and to contribute in this way, to the process of capitalistic accumulation. But, by doing this, it causes a kind of growth, in the housing sector, which is unable to satisfy lower-class needs for houses. 8. The attainment of this last purpose would, therefore, mean an efficient regional planning and the elimination of urban rent, conditions which are in opposition to the maintenance of the present economic and social structure of the Italian economy, of which speculative building and rent sectors are, nowadays, essential components.     

Geomorphological hazards related to deep dissolution phenomena in the Western Italian Alps: Distribution, assessment and interaction with human activities

Deep dissolution affects great part of soluble rocks (e.g. gypsum and anhydrite) of the Western Italian Alps. The related superficial phenomena (sinkholes, gravity-induced processes and a local worsening of geomechanical rock properties) are not limited to typical karsts landscape and cause slope instability also affecting populated sites and infrastructures. The paper aims to describe general characteristic of dissolution phenomena, to interpret their conditioning factors and evolutionary stages and to assess possible hazards due to their superficial effects.The search for evidences of deep dissolution leads to the selection of representative sites in the central part of the Western Italian Alps (Piemonte and Valle d'Aosta Region). Detailed geological and geomorphological studies have been used to classify the selected sites by type, size and variable state of activity. Very different evolutionary stages of dissolution phenomena have been interpreted by comparison of case-studies: some are early “embryonic”; others are more evolved, up to typical sinkholes, or even remodelled by other phenomena. Some cases show an extreme complexity in the interactions between corrosion phenomena and other geomorphic processes: slope deformations, from one side, and karst, fluvial and glacial phenomena, to the other. A wide range of movement rates on slope instabilities induced by deep dissolution have been estimated by topographic and geomorphic data. Geochemical data on removed rocks by dissolution indicate 0.4 mm/year values for local subsidence. Historical and technical data indicate low frequency of major dissolution-induced collapses, but highlight widespread damages to tunnels, roads and buildings, especially along slopes.     

Experimental and analytical evaluation of the consolidation of tower 8 in the Damascus citadel

The object of this work is a building situated in the ancient citadel of Damascus: tower 8 which has been affected by devastating earthquakes and subjected to a consolidation process thanks to the Syrian–Italian Cooperation Project. The aim of this research is to investigate the dynamic characteristics of this consolidated structure. Hence, a mixed procedure of experimental measurements and analytical analysis has been chosen. Considering the geotectonic environment and the historical importance, ambient noise measurements are preferred as being a non-destructive technique and the most suitable for the study purpose. The dynamic characteristics of tower 8 are analyzed experimentally and analytically on the basis of ambient noise measurements, which have been performed on the ground and floors of the tower. With spectral analysis of ambient noise records, the predominant frequencies, amplification factors, and damping ratios have been determined. The experimental and analytical results have allowed verifying the efficiency of the consolidation interventions in tower 8.     

Fake quakes in Italy through parametric catalogues and seismological compilations: case histories and typologies

The Italian catalogue contains many earthquakes of moderate to high epicentral intensity which are located in areas of low seismicity and near big cities. Some of them have been inserted in the catalogue after one historical record only. This study investigates many such events in the 1000–1690 time-window showing that a great number of them are fake. Starting by an operational definition of ‘fake quake’, this paper shows the procedures adopted, and the main results which contribute in a significant way to the reassessment of seismicity and seismic hazard.     

Morphological analysis and features of the landslide dams in the Cordillera Blanca,Peru

Global warming in high mountain areas has led to visible environmental changes as glacial retreat, formation and evolution of moraine dammed lakes, slope instability, and major mass movements. Landslide dams and moraine dams are rather common in the Cordillera Blanca Mountains Range, Peru, and have caused large damages and fatalities over time. The environmental changes are influencing the rivers’ and dams’ equilibrium, and the potential induced consequences, like catastrophic debris flows or outburst floods resulting from dam failures, can be major hazards in the region. The studies of past landslide dam cases are essential in forecasting induced risks, and specific works on this topic were not developed in the study region. Reflecting this research gap, a database of 51 cases and an evolution study of landslide dams in the Cordillera Blanca Mountains is presented. The main morphometric parameters and information of the landslide, the dam body, the valley, and the lake, if any, have been determined through direct and indirect survey techniques. Low variability in some of the main morphometric parameter distributions (valley width and landslide volume) has been shown, most likely due to an environmental control connected to the regional tectonic and glacial history. In order to analyze present and future landslide dam evolution, a morphological analysis was carried out using two recently developed geomorphological indexes employed on the Italian territory. The results of the Cordillera Blanca analysis have been compared with a large Italian landslide dam inventory, highlighting as much the differences as the similarities between the two datasets. The long-term geomorphological evolution changes are evaluated. Many of the stable dams are in disequilibrium with their surrounding environment and their classification result is of “uncertain determination.”     

Correlation of Plio-Pleistocene deposits of the Lower Rhine Basin (North-West Germany) and the Valle Ricca pits (Central Italy)

Biostratigraphic and palaeomagnetic research has been carried out on selected profiles in North-Western Germany and Central Italy in order to correlate Plio-Pleistocene sections.Around the Réunion subchronozone, vegetation in the Valle Ricca was dominated by a mountain forest type pointing to cool climatic conditions. In the Lower Rhine Basin vegetation had a slightly warmer character, but was also dominated strongly by a mountain type of forest vegetation, characteristic of cooler summers and higher precipitation than at present.Two warmer periods have been determined in the Central Italian profiles; the youngest around the Olduvai reversal, should correspond to the youngest Tiglian beds of the Lower Rhine Basin.Deposits older than the Réunion subzone have not been found in the Valle Ricca. In the Lower Rhine Basin, on the other hand, the Gauss-Matuyama boundary is located between the uppermost Pliocene, the Reuverian C and the Praetiglian.